Compute integer range bounds for bitwise AND, OR, XOR, and NOT on IntegerRangeType

src/Reflection/InitializerExprTypeResolver.php

@@ -1063,7 +1063,13 @@ public function getBitwiseAndType(Expr $left, Expr $right, callable $getTypeCall
 		$result = $this->getFiniteOrConstantScalarTypes($leftType, $rightType, static fn ($a, $b) => $a & $b);
 		if ($result instanceof Type) {
 			return $result;
-		} elseif ($result === self::IS_SCALAR_TYPE) {
+		}
+
+		// computed before optimizeScalarType() below widens integer ranges to int
+		$leftNumberType = $leftType->toNumber();
+		$rightNumberType = $rightType->toNumber();
+
+		if ($result === self::IS_SCALAR_TYPE) {
 			$leftType = $this->optimizeScalarType($leftType);
 			$rightType = $this->optimizeScalarType($rightType);
 		}
@@ -1084,18 +1090,13 @@ public function getBitwiseAndType(Expr $left, Expr $right, callable $getTypeCall
 			return new ErrorType();
 		}
 
-		$leftNumberType = $leftType->toNumber();
-		$rightNumberType = $rightType->toNumber();
-
-		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+		if ($leftType->toNumber() instanceof ErrorType || $rightType->toNumber() instanceof ErrorType) {
 			return new ErrorType();
 		}
 
-		if ($rightNumberType instanceof ConstantIntegerType && $rightNumberType->getValue() >= 0) {
-			return IntegerRangeType::fromInterval(0, $rightNumberType->getValue());
-		}
-		if ($leftNumberType instanceof ConstantIntegerType && $leftNumberType->getValue() >= 0) {
-			return IntegerRangeType::fromInterval(0, $leftNumberType->getValue());
+		$bitwiseAndRange = $this->computeBitwiseAndRange($leftNumberType, $rightNumberType);
+		if ($bitwiseAndRange !== null) {
+			return $bitwiseAndRange;
 		}
 
 		return new IntegerType();
@@ -1122,7 +1123,13 @@ public function getBitwiseOrType(Expr $left, Expr $right, callable $getTypeCallb
 		$result = $this->getFiniteOrConstantScalarTypes($leftType, $rightType, static fn ($a, $b) => $a | $b);
 		if ($result instanceof Type) {
 			return $result;
-		} elseif ($result === self::IS_SCALAR_TYPE) {
+		}
+
+		// computed before optimizeScalarType() below widens integer ranges to int
+		$leftNumberType = $leftType->toNumber();
+		$rightNumberType = $rightType->toNumber();
+
+		if ($result === self::IS_SCALAR_TYPE) {
 			$leftType = $this->optimizeScalarType($leftType);
 			$rightType = $this->optimizeScalarType($rightType);
 		}
@@ -1147,6 +1154,11 @@ public function getBitwiseOrType(Expr $left, Expr $right, callable $getTypeCallb
 			return new ErrorType();
 		}
 
+		$bitwiseOrRange = $this->computeBitwiseOrXorRange($leftNumberType, $rightNumberType);
+		if ($bitwiseOrRange !== null) {
+			return $bitwiseOrRange;
+		}
+
 		return new IntegerType();
 	}
 
@@ -1171,7 +1183,13 @@ public function getBitwiseXorType(Expr $left, Expr $right, callable $getTypeCall
 		$result = $this->getFiniteOrConstantScalarTypes($leftType, $rightType, static fn ($a, $b) => $a ^ $b);
 		if ($result instanceof Type) {
 			return $result;
-		} elseif ($result === self::IS_SCALAR_TYPE) {
+		}
+
+		// computed before optimizeScalarType() below widens integer ranges to int
+		$leftNumberType = $leftType->toNumber();
+		$rightNumberType = $rightType->toNumber();
+
+		if ($result === self::IS_SCALAR_TYPE) {
 			$leftType = $this->optimizeScalarType($leftType);
 			$rightType = $this->optimizeScalarType($rightType);
 		}
@@ -1196,6 +1214,11 @@ public function getBitwiseXorType(Expr $left, Expr $right, callable $getTypeCall
 			return new ErrorType();
 		}
 
+		$bitwiseXorRange = $this->computeBitwiseOrXorRange($leftNumberType, $rightNumberType);
+		if ($bitwiseXorRange !== null) {
+			return $bitwiseXorRange;
+		}
+
 		return new IntegerType();
 	}
 
@@ -1985,6 +2008,78 @@ private function optimizeScalarType(Type $type): Type
 		return new UnionType($types);
 	}
 
+	/**
+	 * @return array{int, int}|null [min, max] or null if bounds are not known
+	 */
+	private function getNonNegativeIntegerBounds(Type $type): ?array
+	{
+		if ($type instanceof IntegerRangeType) {
+			$min = $type->getMin();
+			$max = $type->getMax();
+			if ($min !== null && $min >= 0 && $max !== null) {
+				return [$min, $max];
+			}
+			return null;
+		}
+		if ($type instanceof ConstantIntegerType && $type->getValue() >= 0) {
+			return [$type->getValue(), $type->getValue()];
+		}
+		return null;
+	}
+
+	/**
+	 * Expects the operands already converted with toNumber().
+	 *
+	 * A single non-negative operand is enough to bound the result: the result's bits
+	 * are a subset of that operand's bits, so it stays within int<0, thatMax>.
+	 */
+	private function computeBitwiseAndRange(Type $leftNumberType, Type $rightNumberType): ?Type
+	{
+		$leftBounds = $this->getNonNegativeIntegerBounds($leftNumberType);
+		$rightBounds = $this->getNonNegativeIntegerBounds($rightNumberType);
+		if ($leftBounds !== null && $rightBounds !== null) {
+			return IntegerRangeType::fromInterval(0, min($leftBounds[1], $rightBounds[1]));
+		}
+		if ($leftBounds !== null) {
+			return IntegerRangeType::fromInterval(0, $leftBounds[1]);
+		}
+		if ($rightBounds !== null) {
+			return IntegerRangeType::fromInterval(0, $rightBounds[1]);
+		}
+		return null;
+	}
+
+	/**
+	 * Expects the operands already converted with toNumber().
+	 */
+	private function computeBitwiseOrXorRange(Type $leftNumberType, Type $rightNumberType): ?Type
+	{
+		$leftBounds = $this->getNonNegativeIntegerBounds($leftNumberType);
+		$rightBounds = $this->getNonNegativeIntegerBounds($rightNumberType);
+		if ($leftBounds === null || $rightBounds === null) {
+			return null;
+		}
+		$maxValue = max($leftBounds[1], $rightBounds[1]);
+		$upperBound = self::allBitsMask($maxValue);
+		return IntegerRangeType::fromInterval(0, $upperBound);
+	}
+
+	/**
+	 * Propagates the highest set bit of a non-negative value into all lower bits:
+	 * 200 becomes 255, 10 becomes 15.
+	 */
+	private static function allBitsMask(int $value): int
+	{
+		$value |= $value >> 1;
+		$value |= $value >> 2;
+		$value |= $value >> 4;
+		$value |= $value >> 8;
+		$value |= $value >> 16;
+		$value |= $value >> 32;
+
+		return $value;
+	}
+
 	/**
 	 * @return TypeResult<BooleanType>
 	 */

src/Type/IntegerRangeType.php

@@ -511,6 +511,15 @@ public function toAbsoluteNumber(): Type
 		return self::fromInterval(-$this->max, $inversedMin);
 	}
 
+	public function toBitwiseNotType(): Type
+	{
+		// ~int<a, b> = int<~b, ~a>  (bitwise NOT reverses the order)
+		return self::fromInterval(
+			$this->max !== null ? ~$this->max : null,
+			$this->min !== null ? ~$this->min : null,
+		);
+	}
+
 	public function toString(): Type
 	{
 		$finiteTypes = $this->getFiniteTypes();

tests/PHPStan/Analyser/nsrt/bug-14654.php

@@ -0,0 +1,90 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14654;
+
+use function PHPStan\Testing\assertType;
+
+function foo(): void {
+	$a = \ord('a');
+	$b = \ord('b');
+
+	assertType('int<0, 255>', $a);
+	assertType('int<0, 255>', $b);
+	assertType('int<0, 255>', $a ^ $b);
+	assertType('int<0, 255>', $a | $b);
+	assertType('int<0, 255>', $a & $b);
+}
+
+/**
+ * @param int<0, 255> $c
+ */
+function withConstantOperand(int $c): void {
+	assertType('int<0, 255>', $c ^ 42);
+	assertType('int<0, 255>', 42 ^ $c);
+	assertType('int<0, 255>', $c | 42);
+	assertType('int<0, 42>', $c & 42);
+}
+
+/**
+ * @param int<0, 255> $c
+ */
+function withOperandCoercedToInteger(int $integer, int $c): void {
+	assertType('int<0, 3>', $integer & '3');
+	assertType('int<0, 3>', '3' & $integer);
+	assertType('int<0, 1>', $integer & true);
+	assertType('int<0, 255>', $c ^ '3');
+	assertType('int<0, 255>', $c | '3');
+	assertType('int<0, 3>', $c & '3');
+}
+
+/**
+ * @param int<0, 20> $x
+ * @param int<0, 20> $y
+ */
+function smallRanges(int $x, int $y): void {
+	assertType('int<0, 31>', $x ^ $y);
+	assertType('int<0, 31>', $x | $y);
+	assertType('int<0, 20>', $x & $y);
+}
+
+/**
+ * @param int<0, 255> $a
+ * @param int<0, 20> $x
+ */
+function differentRangeSizes(int $a, int $x): void {
+	assertType('int<0, 20>', $a & $x);
+	assertType('int<0, 20>', $x & $a);
+}
+
+/**
+ * @param int<0, max> $unbounded
+ * @param int<0, 255> $a
+ */
+function unboundedRanges(int $unbounded, int $a): void {
+	assertType('int', $unbounded ^ $a);
+	assertType('int', $unbounded | $a);
+	assertType('int<0, 255>', $unbounded & $a);
+}
+
+/**
+ * @param int<-10, 10> $signed
+ * @param int<0, 20> $x
+ */
+function negativeRanges(int $signed, int $x): void {
+	assertType('int', $signed ^ $x);
+	assertType('int', $signed | $x);
+	assertType('int<0, 20>', $signed & $x);
+}
+
+/**
+ * @param int<0, 255> $a
+ * @param int<0, 20> $x
+ * @param int<min, 10> $minBounded
+ * @param int<-5, max> $maxBounded
+ */
+function bitwiseNot(int $a, int $x, int $minBounded, int $maxBounded): void {
+	assertType('int<-256, -1>', ~$a);
+	assertType('int<-21, -1>', ~$x);
+	assertType('int<-11, max>', ~$minBounded);
+	assertType('int<min, 4>', ~$maxBounded);
+}